Question

What is the standard form of # y=(x - 8) (x + 10) #?

Answer 1

Check out the explanation.

Explanation:

I would highly recommend using the FOIL method, a mnemonic device that I was taught in my Algebra class. It's simple and very easy to learn and memorize.

So first, let's start off with the equation:

`y=(x-8)(x+10)`

Using the FOIL method, I will:

• Multiply the `x` in the first set of parenthesis by the `x` in the second set of parenthesis

`x^2`

• Multiply the `x` in the first set of parenthesis by the `10` in the second set of parenthesis

`+10x`

• Multiply the `-8` in the first set of parenthesis by the `x` in the second set of parenthesis

`-8x`

• Multiply the `-8` in the first set of parenthesis by the `10` in the second set of parenthesis.

`-80`

Now let's combine them all together into one equation:

`y=x^2+10x-8x-80`

And let's simplify that equation by combining like terms (in this case it's the two numbers that share `x` as a variable, `10x` and `-8x`). To combine them, all I did was subtract `10x` and `-8x`:

• `y=x^2+2x-80`

And there's your answer!

Edit: and here's a picture of the FOIL method.